1. field of the Invention
Relates to SONAR devices and more particularly to airplane dropped submarine locating devices known as sonobuoys.
2. Description of the Prior Art
Presently, final submarine localization and attack phases by ASW (anti-submarine warfare) aircraft must be carried out at low altitude (less than 5,000 feet). This exposes the aircraft to potential underwater-to-air missile attack, leads to poor fuel economy and small radio-radar horizon, decreases aircraft speed and fatigue life and gives poor crew ride. The use of a Cubic-type Sonobuoy Reference System in conjunction with the high altitude sonobuoy would allow ASW search operations to be carried out from high altitudes. Present sonobuoys are not feasible for high altitude deployment because of potential placement errors in wind conditions.
For high altitude deployment, the sonobuoy must be equipped with means for causing the initial fall according to a ballistic trajectory and then means for slowing the rate of descent prior to water impact. The sonobuoy thus equipped must also be capable of storage and launch from standard sonobuoy launching tubes presently installed on ASW Aircraft.
Rotovanes have proved to be a satisfactory means for slowing the descent of a sonobuoy launched from lower altitudes. Baroswitches are well known as devices for activating a mechanism as a function of altitude. Fins have been known for their stabilizing effect since the invention of the arrow. Combining these elements with a sonobuoy such that they can be stored and deployed from a standard sonobuoy launching tube in the manner of the present invention, however, does not appear in the prior art. Various combinations of folding fins and breaking devices were disclosed by a search of the prior art but none disclosed or suggested the apparatus of the present invention.
The U.S. Pat. No. 3,057,589 of Nutkins, et al. discloses a two position rotor that serves first as a fin and then as a rotor. This apparatus, however, does not have the required third position for use on a sonobuoy wherein the fin is also folded so that the sonobuoy can be stored in the launch tube.
The patents of Suter (U.S. Pat. No. 3,588,004 and 3,598,345) disclose a folding brake and fin combination which could be mounted on a sonobuoy to fit in a launching tube. The disclosed apparatus, however, requires that the brake and fin deploy simultaneously where, for the intended purposes, the fin must deploy separate from the brake.
The device of Jackson as disclosed in U.S. Pat. No. 3,098,445 has the same limitation as that of Nutkins, et al. in that in the fin position the dual purpose rotor does not fold to allow storage in the launch tube.
The missile of Hubich disclosed in his U.S. Pat. No. 3,643,599 most closely approximates the functions of the present invention. Hublich combines fins, breaking and folding in one device. The manner is patentably distinct from the present invention, however, in that a drag brake having no lift is employed and, to function and fold, the fin is required to have its major axis perpendicular to the missile body axis instead of the conventional and more effective method of having the major axis parallel to the missile body axis as used by the present invention, Jackson, Suter, and Nutkins, et al.
Thus, it is an object of the present invention to provide a sonobuoy having effective stabilizing fins and a rotovane breaking device employing airfoil rotors with lift which can be stored and launched from a conventional sonobuoy launch tube.
It is a further object of the present invention to provide a sonobuoy with folding fins and rotovanes wherein the fins and rotovanes can be deployed separately.